lovecoding
/
w1020


			
				
					
						
						
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							<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        html{
            font-size: 20px;
        }
        .box{
            font-size: 30px;
        }
        .div1{
            /* rem 单位是相对于html的font-size   相当于 rem乘html的font-size */
            /* width: 10rem;
            height: 10rem; */

            /* em 单位是相对于父元素的font-size */
            height: 10em;
            width: 10em;
            background-color: red;
        }
    </style>
</head>
<body>
    <div class="box">
        <div class="div1"></div>
    </div>
</body>
</html>